This is the real stories from my own experiences...
I no longer working in this office since I changed to a new company. It's been 5 years I working in this office. This office is located in a reserved jungle in Kuala Lumpur, which opposite of Bukit Tunku (Kenny Hill). For your all information, there are full of government offices.
Back in my first year work in that office, I used to stay until late night or overnight in that office due to some emergency work. The first few times I don't feel or heard anything weird happened. Until one night, I was on call duty and back to the office on a weekend late night, I decided to stay overnight there since it was so late.
After the work done, I slept in the control center room with my another colleague who work in night shift. In the midnight I was waken up by something, I not sure what was that, but when I woke up, I saw my colleague still in deep sleep and snoring so loud. The most weird thing is... I heard a second snoring sound in that room! The snoring sound is from the other corner and I'm very sure the sound is not from my colleague because he just slept next to me. At that time, just only me and my colleague in the office.
This is another story... it was festive season and public holiday, I never went back to my hometown because I was the only person who on duty. That time I was busy with my part time study final year thesis, so I stayed in that office for few days to complete the paper work. It was my most worst moment to stay there during that few nights in my life. The whole office only left another colleague who have to stay in control room, and I was in my own office room all the time, both of us were in different floor. I always heard 'someone' is knocking my door, got table or chairs movement sound from my next door room. I really felt I was not alone on that floor.
Sometimes I got some weird intercom calls. My phone rang and when I pickup, no body was talking and I only heard some noise that like radio out of signal sound. When I looked at the display and make sure from which extension, the display showed nothing!
One time I went to my Headquarters to help me friend do some works, my headquarters just few blocks away from my office. It was going to late evening, we heard someone was running upstairs. For your information, the floor is made from concrete but the running footsteps sound is like running on a wooden building! The sound keeps repeating from one end to another end, so I decided to check it out who was there. When I was at that level, I see no body on that floor. Then I went to check with the security guard, guess what he told me? "That's normal and there is 'something' out there!"
After I checked with some colleagues who work many years there, all also told me the same answer, each floor got different 'Thing' out there and got one even scary... it can changed to a person face exactly the same, one of the guard met before and he told me, he was open the door early in the morning before we all came to work, suddenly he saw one of our accountant was sitting on her desk then slowly faded and gone. Another colleague saw 'another' person walking on the corridor at night, in fact that person was not in the office! That's really scary!